<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    let arr = [12, 66, 4, 88];
    let narr = arr.filter(function (v, i) {
      return v >= 20;
    })
    console.log(narr)
  </script>
</body>

</html>